Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine, University of São Paulo, São Paulo, SP, Brazil.
Ticks Tick Borne Dis. 2011 Dec;2(4):209-12. doi: 10.1016/j.ttbdis.2011.08.003. Epub 2011 Oct 17.
A total of 130 adult free-living ticks of Amblyomma cajennense and 9 free-living Amblyomma dubitatum were collected in the surroundings of the Pampulha Lake, within Belo Horizonte city, state of Minas Gerais, south-eastern Brazil. Each adult tick was tested for rickettsial infection by PCR protocols targeting the rickettsial genes gltA, htrA, and ompA. All the 130 A. cajennense ticks were negative by PCR. In contrast, all 9 A. dubitatum ticks were shown to contain rickettsial DNA. PCR products were sequenced, generating identical sequences for each gene among the 9 ticks, which were shown to contain a novel agent, here designated as Rickettsia sp. strain Pampulha. Phylogenetic analyses inferred from the 3 rickettsial genes (gltA, htrA, ompA) showed that Rickettsia sp. strain Pampulha segregated in the same cluster with R. tamurae, R. monacensis, and several other unclassified rickettsial strains; however, strain Pampulha is a unique Rickettsia strain for the New World, since its closest relatives, according to 3 genes (gltA, htrA, and ompA), are all from the Old World. Because A. dubitatum eventually bites humans, further studies are necessary to determine the potential pathogenicity of Rickettsia sp. strain Pampulha to humans.
总共从巴西东南部米纳斯吉拉斯州贝洛奥里藏特市附近的潘普利亚湖周围采集到 130 只自由生活的铠恙螨和 9 只自由生活的钝缘蜱。通过针对立克次体基因 gltA、htrA 和 ompA 的 PCR 方案检测每只成年蜱的立克次体感染情况。PCR 结果显示，130 只铠恙螨均为阴性。相比之下，9 只钝缘蜱均显示含有立克次体 DNA。PCR 产物进行测序，9 只蜱的每个基因都产生了相同的序列，这些序列包含一种新的病原体，在此命名为潘普利亚拉卡西亚斯。来自 3 个立克次体基因（gltA、htrA 和 ompA）的系统发育分析表明，潘普利亚拉卡西亚斯与拉卡西亚斯、单核细胞增多症和其他几个未分类的立克次体菌株聚类在一起；然而，根据 3 个基因（gltA、htrA 和 ompA），潘普利亚拉卡西亚斯是新世界的一种独特的拉卡西亚斯菌株，因为其最接近的亲缘关系都来自旧世界。由于钝缘蜱最终会叮咬人类，因此需要进一步研究来确定潘普利亚拉卡西亚斯对人类的潜在致病性。
